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Biomedical subjects

M R Platt

Publications and source records attributed to M R Platt.

At least 19 recordsLinked to original sources
PubMed1990

Systemic arterial air embolism in penetrating lung injury.

Systemic arterial air embolism is frequently unrecognized as a cause of death among patients with isolated penetrating lung injury. Between 1975 and 1983 at Parkland Memorial Hospital, the complication of systemic arterial air embolism developed in 9 patients with penetrating lung injury (six gunshots and three stabbings). Eight patients were either in profound shock or experienced cardiac arrest and all were intubated and on positive-pressure ventilation, frequently on a manual resuscitator bag before or at the time of diagnosis. The diagnosis was made by direct visualization of air in the coronary vessels in all 9 patients, and in 3 air was also aspirated from the left ventricular apex and aortic root. In addition, 5 patients had clinically significant hemoptysis. At operation, only an isolated injury to the lung was found in 7 of the 9 patients. Arterial air embolism is a highly lethal complication; 6 of our patients died, a mortality rate of 66%. Thus, it clearly behooves us to be more alert to the possible occurrence of this complication among all victims of penetrating chest trauma. We must accept that systemic arterial air embolism is an established complication of penetrating lung injury and must recognize that it occurs much more frequently than has been previously reported. Prompt diagnosis coupled with aggressive efforts at cardiopulmonary resuscitation is crucial for successful management of patients with air embolism.

Adolescent↗
PubMed1986

Corrosive burns of the esophagus and stomach: a recommendation for an aggressive surgical approach.

During a six-year period ending in December, 1980, 62 patients with a history or clinical evidence of corrosive ingestion were admitted into our institutions. The majority were adults who had attempted suicide. Strong alkali (lye), the most common corrosive agent involved, was ingested by more than half of the patients (39). The remaining 23 patients had ingested weak alkali or nonalkali corrosive agents. Of the 27 patients with severe esophagogastric burns (second- and third-degree), a 43.5% incidence overall, liquid lye was responsible in 21, including 7 of 8 patients with extensive full-thickness esophagogastric necrosis. In sharp contrast, only 1 of the 23 patients who had ingested weak alkali or nonalkali corrosive agents had serious esophagogastric injury. In the first two years of this review, the management approach was the so-called standard one (esophagoscopy, steroids, antibiotics, and dilation) (Group 1). The results were disappointing. In 5 of 9 patients with endoscopic findings of second-degree burns, stricture requiring dilation developed, and all 4 with extensive full-thickness esophagogastric necrosis died. In contrast, during the last four years, with the adoption of a more aggressive surgical approach, that is, early surgical intervention including the use of an intraluminal esophageal stent and radical resection as indicated, missed or delayed diagnosis of full-thickness esophagogastric necrosis with its prohibitive mortality was avoided and the complication of severe esophageal stricture was virtually eliminated (Group 2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Descending necrotizing mediastinitis.

From January 1975 through July 1981, ten patients with mediastinitis complicating an oropharyngeal infection, that is, a form of mediastinitis best termed as DNM, were encountered at our institution. Based upon rather relatively stringent diagnostic criteria, 21 other instances were found in the literature from 1960 to 1980, a time period well into the antibiotic era. The predominant underlying oropharyngeal infection was of odontogenic origin, specifically, infection involving the mandibular molars. Bacteriologically, DNM is most frequently a polymicrobial process, with anaerobes playing a major role. Although there has been a decline in the over-all incidence of DNM since the introduction of antibiotics, its morbid and lethal nature persists, as evidenced by the present prohibitive mortality of approximately 42 per cent. Delayed diagnosis and inadequate drainage procedures are the primary underlying factors contributing to this high mortality. At present, CT scan is the single most important tool for the early diagnosis of DNM. This noninvasive procedure also helps determine the adequacy of the surgical drainage procedure performed. However, with all the presently available diagnostic tools, it is still the high index of suspicion by physicians toward patients with unrelenting oropharyngeal or deep neck infection that is of utmost importance for making an early diagnosis of DNM. In view of our experience and that of others, we believe that only through aggressive combined medical and surgical management can the highly morbid, if not lethal, course of DNM be reversed. It should be emphasized that, to accomplish successful operative intervention, a thorough knowledge of the complex anatomy of the region is crucial.

Abscess↗
PubMed1982

Massive pulmonary embolism: a complication of the technique of tourniquet ischemia.

Various neurologic and vascular injuries complicating the technique of tourniquet ischemia for limb surgery are well known. We found no reports of the serious complication of massive pulmonary embolism as a consequence of this technique. This is surprising when one considers the type of patients surgeons deal with in the use of the technique of tourniquet ischemia. These patients are traumatized and immobile, with high potential for development of deep venous thromboembolic disease, and are subjected to extensive extremity manipulation. Such patients are ideal candidates for the development of massive pulmonary embolism. We have encountered and successfully treated a patient with such a complication.

Adolescent↗
PubMed1981

Pulsatile sternal tumor: report of three cases and a review of the literature.

At our institution, 3 patients with pulsatile sternal tumor have been seen. Although ascending aortic aneurysm frequently is high on the list of differential diagnoses, the likelihood that this tumor is metastatic from either a primary renal or thyroid neoplasm is overwhelming. Of the 15 patients reported, 11 had metastases from a primary renal cell carcinoma, including all 3 of our patients. There were 2 patients with primary myeloma, the only histologically proved primary pulsatile sternal tumor. From the surgical standpoint, only the patient with metastatic renal cell carcinoma has a chance of cure. With the recent report of 2 5-year survivors and our own experience of 1 patient with a long asymptomatic interval following resection of the primary kidney tumor and the secondary sternal metastasis, the attitude of hopelessness for these patients should be challenged and an aggressive approach considered.

Adult↗
PubMed1981

Intraaortic balloon counterpulsation: its influence alone and combined with various pharmacological agents on regional myocardial blood flow during experimental acute coronary occlusion.

We investigated the separate and combined effects of pharmacological and intraaortic balloon pump (IABP) support on regional myocardial blood flow in an experimental model of acute myocardial ischemia. Chloralose-anesthetized dogs were ventilated with an oxygen-air mixture, and cardiac output, arterial pressure, and heart rate were held constant. Treatment was begun 20 minutes following permanent ligation of the left anterior descending coronary artery (LAD). We evaluated the following pharmacological interventions: 25% hypertonic mannitol, isosorbide dinitrate, methyl-prednisolone sodium succinate, and propranolol. We measured left ventricular hemodynamics and intramyocardial blood flow by the radioactive microsphere technique prior to treatment and at 15-minute intervals thereafter. Compared with control measurements 20 minutes following LAD ligation, collateral blood flow to ischemic myocardium tended to decrease with no treatment. Treatments with the four pharmacological interventions and with IABP alone produced no significant improvement in collateral blood flow to ischemic myocardium 15 minutes following treatment. In contrast, mannitol, isosorbide dinitrate, and propranolol, each combined with IABP support, produced significant improvements in collateral flow within the same time periods. In nonischemic myocardium, combined pharmacological and IABP treatment did not enhance myocardial blood flow above that obtained with the pharmacological agents alone. The most effective combination of mechanisms for improving the ischemic region's myocardial blood flow appeared to be a reduction of extravascular coronary flow resistance coupled with a simultaneous increase in diastolic arterial pressure.

Animals↗
PubMed1980

Rupture of the right hemidiaphragm with liver herniation: report of a case with extension of a tear of a previously undiagnosed ruptured right hemidiaphragm.

Right-sided blunt diaphragmatic rupture is not uncommon. Its incidence has definitely increased. As expected, total or partial herniation of the liver commonly occurs with this entity. Diaphragmatic-pericardial rupture with visceral herniation into the pericardial cavity and other rare injuries have been diagnosed, but we found no report of extension of a diaphragmatic tear of a previously undiagnosed right-sided diaphragmatic rupture with total herniation of the liver. Such a case is reported here.

Accidents, Traffic↗
PubMed1980

Marked thrombosis and calcification of porcine heterograft valves.

Prosthetic valvular dysfunction resulting in clinically significant complications occurred in six patients with Hancock porcine heterografts. In one patient with a prosthetic valve in the aortic position, massive prosthetic thrombosis resulted in sudden death. In two patients who had a mitral prosthesis, thrombosis resulted in congestive heart failure and systemic embolization; in one of the latter patients, the thrombi were infected with Candida sp. Calcification of organizing thrombi and cusp tissue resulted in valvular stenosis and congestive heart failure in one patient with an aortic prosthesis and in two patients with mitral prostheses. Four of the six patients died. The prosthetic valves had been in place for 6 months to 3 years before onset of complications. During the same 4-year interval, over 400 porcine prosthese were inserted. This report provides further clarification of the nature and frequency of clinical complications related to degeneration and thrombosis of Hancock porcine heterograft valves.

Adult↗
PubMed1979

Avoidance of esophageal stricture following severe caustic burns by the use of an intraluminal stent.

The high incidence of stricture following conventional therapy for caustic esophageal injuries prompted us to incorporate the esophageal stenting technique of Reyes and colleagues [3, 5, 6] into our protocol for management of such patients. Four adult patients were treated following severe esophageal burns caused by the ingestion of caustic drain cleaner. The severity of the burn was established by early esophagoscopy. Laparotomy and gastrotomy revealed severe but nontransmural gastric burns. The stent was left in place for 21 days. Antibiotics and corticosteroids were also employed. There have been no late strictures. One patient required laryngeal dilation for adhesions and another, tracheal dilation for subglottic stenosis. Contrast roentgenographic studies and esophageal manometry have revealed nearly normal esophageal function up to 20 months following the injury.

Adolescent↗
PubMed1979

Influence of aging on left ventricular hemodynamics and stiffness in beagles.

We studied the influence of aging on the contractile performance, stiffness, and contraction time of the canine left ventricle. Eight young (27 +/- 2.5 months, mean +/- SE) and seven old (128 +/- 20.5 months) beagles were placed on complete cardiopulmonary bypass, the arterial pressure was adjusted to 80 mm Hg, and the heart contracted isovolumically at a paced rate of 120 beats/min. Diastolic pressure-volume curves were established for each unpaced left ventricle at the beginning of each experiment, and the volume at the knee of the curve was used during the subsequent data collection when the heart was paced. Stiffness was measured with a sinusoidal forcing function, which imposed a sinusoidal displacement of 1 ml at 20 Hz into a balloon placed in the left ventricle. In each ventricle, stiffness was related linearly to pressure during the cardiac cycle, and was greater for any given pressure in the older beagles. Contraction duration was prolonged in the older dogs. In an additional seven old beagles during right heart bypass time, and duration of contraction were longer than in seven young beagles. Aging of the beagle heart is associated with an increase in left ventricular systolic and diastolic stiffness and prolonged duration of contraction.

Aging↗
PubMed1979

Traumatic injuries of the diaphragm.

Traumatic injury of the diaphragm is not an infrequent occurrence. With the rise in violence and increasing use of automobiles, more diaphragmetic injuries may be seen, especially in inner-city hospitals. Sixty-six cases from our institution within the last five years were reviewed. Of these there were 41 penetrating injuries and 23 secondary to blunt trauma. Two cases were surgically induced following a difficult decortication for pleuropulmonary tuberculosis. There were ten deaths (15 percent mortality). All deaths were related to the severity of associated injuries. In addition, we analyzed 307 patients with multiple injuries who were dead on arrival and were autopsied by the county medical examiners in a 24-month period. Of the 307 autopsied cases, 16 (5.2 percent) had ruptured diaphragms. Interestingly, all but one of these cases were associated with thoracic aortic injuries. Diagnoses of penetrating diaphragmatic injuries were made during exploration of other injuries. In blunt diaphragmatic rupture, a high index of suspicion in most important in the diagnosis. In 10 of 23 blunt injuries, visceral herniation was noted on initial x-ray films. In four, follow-up films several hours to a day later showed loops of bowel in the chest. In nine cases, there were no apparent visceral herniations on initial films, and in these, the diagnosis was made during surgery for other indications. The surgical approach to diaphragmatic injuries is individualized. Acute left-sided injuries are best approached through the abdomen. Acute right-sided injuries and all chronic injuries should be approached through the chest.

Adolescent↗
PubMed1979

Tuberculous aneurysms of the descending thoracic aorta: report of a case with fatal rupture.

Tuberculous aortic aneurysm is a rare disease entity. The majority of affected patients succumb to perforation and exsanguination. The only chance for survival and cure is by resection and prolonged antituberculosis chemotherapy. Our case illustrates the high risk of rupture of tuberculous aortic aneurysms. Post-mortem examination revealed that the mechanism of aneurysm formation was by direct caseous involvement of the descending thoracic aorta from a juxtaposed left upper lobe parenchymal tuberculous process. Our findings also favor the concept that miliary dissemination (in the presence of tuberculous aortic aneurysm) is the result rather than the cause of the tuberculous aortic process.

Aorta, Thoracic↗